Feed collet



I. H. SHEFFER Dec; 11, 1934.

FEED COLLET Filed Sept. 6, 1933 INVENTOR. fifiy e z ATTORNEY.

Patented Dec. 11, 1934 UNITED STATES P/ATENT OFFICE 4 Claims.

This invention relates toimprovements in feed collets used in automatic machines and the like for feeding stock axially through hollow spindles.

It is an object of the invention to provide a feed collet having a plurality of longitudinal slots formed therethrough intermediately of its length thereby dividing that portion of the collet into a plurality of fingers of uniform width oneach of which an inwardly projecting segmental gripping member is formed; and to afford means for exerting inward circumferential spring tension uniformly along the full length of the gripping members.

Another object of the invention is to provide such a feed collet which is substantially of uniform diameter throughout its entire length, and which is so constructed that as the gripping members wear andthey no longer firmly engage and feed the stock axially, the fingers may be inwardly deflected sufficiently to render the members again thoroughly efiicient along their entire length by striking these members lightly with a hammer.

A further object of the invention is to provide such a feed collet wherein th longitudinal slot extends through the front extremity of the collet and the remaining slots terminate at their front extremities in enlarged openings thereby rendering the front ends of the fingers narrower and more resilient.

Yet another object of the invention is to provide such a feed collet wherein the longitudinal margins of the fingers are outwardly chamfered to increase their resilience and also to permit their ready inward deflection rearwardly of the gripping members.

With these and other objects and advantages in view which will become apparent as the specification proceeds, the invention is hereinafter more fully described with the aid of the accompanying drawing, in which:

Figure 1 illustrates a side elevation of the invention.

Figure 2 is another side elevation showing the front split collar, and in this case the enlarged opening which connects one of the intermediate slots with the collar slot is shown multi-sided.

Figures 3 and 4 are enlarged sections on the lines 3-3 and 44 respectively of Figure 1, and

Figure 5 is an enlarged front elevation of Figure 1.

Referring to the drawing, 1 designates a tubular body the outside diameter of which is substantially uniform throughout its length. At its rear extremity the body 1 is circumferentially closed and is provided with means for attachment to an operating membernot' shown. In the present instance the attaching means con-i sists of an external screw thread 3.

Intermediately of its length the body 1 is longitudinally slotted at 4, thereby dividing that portion of the body into a plurality of fingers 5 of equal and uniform width. At the front extremities the slots 4 terminate in enlarged openings which may either be circular as shown at 7, or multi-sided as shown at 7a.' Extending forward from one of the openings '7, or 7a, is a front'slot 7b, in the present instance the same width as the opening 7 or 7a from which it extends; this slot 7b continues to the front extremity of the collet thereby forming a split collar 6 at that extremity. In this manner resilient elements 9 of reduced width are formed at the front ex-: tremities of the fingers 5 which connect the latter with the collar 6.

Intermediately of the length of the body 1 cpposed inwardly disposed gripping members 8 are formed one integral with each finger 5. These members are in the present instance shown of the required form for handling circular stock, but obviously their inwardly disposed faces may be shaped to engage stock of other cross sectional form when desired.

The bore of the body 1 rearwardly of the members 8 and in the collar 6 is of the same diameter. The bore of that portion of the body wherein the elements 9 are formed is of somewhat greater diameter thereby adding to the resiliency of the front extremities of the fingers 5 by making the said elements thinner than the collar. The sides of the slots 4 are usually chamfered as shown at 10. Any desired shape of cutter may be employed for this purpose; two differently shaped chamfers are shown at 10a and 10b in Figure 3. l1 denotes an opening formed through the body to receive a wrench for tightening the threads 3 in the operating member.

By chamfering the sides of the slots 4 as shown at 10, 10a or 10b, the fingers 5 rearwardly the gripping members 8 are rendered not only more resilient; but, due to the reduction in the cross sectional area of the fingers thus obtained it is found that by tapping them inwards lightly with a hammer rearwardly of the members 8 the fingers are readily inwardly flexed so that the bearing surfaces of the members when worn may be readily adjusted for radial spacing. The increased bore of the elements 9, which amounts to an undercut in the body bore, similarly provides portions which may be readily inwardly deflected so that the front extremities of the members 8 may also be moved slightly towards one another. Thus provision is made of deflecting the entire length of the members 8 inwardly so that they contact the stock to be engaged by them throughout their entire length. The collar 6 of course also adds to the resilience of the structure and limits the inward deflection off; the elements 9.

While in the foregoing the preferred embodiment of the invention has been described and shown, it is understood that the invention is susceptible to such alterations and variations as fall within the scope of the appended claims.

What I claim is: g

1'; A feed collet comprising a tubular body provided at one'extremity with means for attachment to an operating member, said body having a plurality of slots formed therethrough intermediately of its length thereby forming a plurality of fingers between them, opposed inwardly projecting gripping members formed on said fingers to engage stock extending through the collet, each slot being of uniform width throughout its length and terminating in an opening of enlarged Width at its front extremity, said openings occurring forwardly of said fingers and the front of the body terminating in a collar split by a slot extending forward from one of said openings.

2. A feed collet comprising a tubular body of substantially uniform diameter throughout its ally engaging stock extending through the feed collet, the body immediately in front of the gripping" members having a plurality of openings wider than said slots formed therethrough in each of which one of the slots terminates, the portion of the body through which the openings are formed being thinner than the fingers and gripping members through which the slots extend, the front of the body terminating in a collar split by a slot extending from one of said openings.

A feed collet comprising a tubular body provided at its rear extremity with means for attachment to an operating member, said body having a plurality of longitudinal slots formed therethrough intermediately of its length thereby forming fingers between them, opposed inwardly projecting gripping members on said fingers, the wall of the body immediately in front of the members being of lesser thickness than the remainder of the body wall and having openings of greater width than said slots formed therethrough in which the front extremities of the slots terminate, and the front of the body terminating in a collar split by a slot extending from one of the openings.

4, A feed collet comprising a tubular body of substantially uniform diameter throughout its length and provided with means for attachment to an operating member, said body having a plurality of longitudinal slots formed therethrough intermediately of its length thereby'forming fingersi between them, gripping members formed on said fingers and projecting inwardly; the outer longitudinal margins of the slots being chamfered, the portion oi the body immediately in front of the gripping members having openings of greater Width than said slots formed therethrough in which said slots terminate, and the front of the body terminating in a collar split by a slot extending from one of the openings.

IRVING I-I. SI-IEFFER. 

